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SubjectRE: [RFC PATCH V2 3/4] crypto: Add Xilinx SHA3 driver
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Hi Corentin,

Sorry for the delayed response.
Please find my responses inline.

> -----Original Message-----
> From: Corentin Labbe <clabbe.montjoie@gmail.com>
> Sent: Thursday, January 10, 2019 7:28 PM
> To: Kalyani Akula <kalyania@xilinx.com>
> Cc: herbert@gondor.apana.org.au; davem@davemloft.net; linux-
> crypto@vger.kernel.org; linux-kernel@vger.kernel.org; Kalyani Akula
> <kalyania@xilinx.com>; Sarat Chand Savitala <saratcha@xilinx.com>
> Subject: Re: [RFC PATCH V2 3/4] crypto: Add Xilinx SHA3 driver
>
> On Wed, Jan 09, 2019 at 02:56:24PM +0530, Kalyani Akula wrote:
> > This patch adds SHA3 driver support for the Xilinx ZynqMP SoC.
> >
> > Signed-off-by: Kalyani Akula <kalyani.akula@xilinx.com>
> > ---
> > drivers/crypto/Kconfig | 10 ++
> > drivers/crypto/Makefile | 1 +
> > drivers/crypto/zynqmp-sha.c | 305
> > +++++++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 316 insertions(+), 0 deletions(-) create mode
> > 100644 drivers/crypto/zynqmp-sha.c
>
> Hello
>
> I have some comment below
>
> > +static int zynqmp_sha_update(struct ahash_request *req) {
> > + const struct zynqmp_eemi_ops *eemi_ops =
> zynqmp_pm_get_eemi_ops();
> > + struct zynqmp_sha_ctx *tctx = crypto_tfm_ctx(req->base.tfm);
> > + struct zynqmp_sha_dev *dd = tctx->dd;
> > + size_t dma_size = req->nbytes;
> > + dma_addr_t dma_addr;
> > + char *kbuf;
> > + int ret;
> > +
> > + if (!req->nbytes)
> > + return 0;
> > +
> > + if (!eemi_ops || !eemi_ops->sha_hash)
> > + return -ENOTSUPP;
> > +
> > + kbuf = dma_alloc_coherent(dd->dev, dma_size, &dma_addr,
> GFP_KERNEL);
> > + if (!kbuf)
> > + return -ENOMEM;
> > +
> > + scatterwalk_map_and_copy(kbuf, req->src, 0, req->nbytes, 0);
> > + __flush_cache_user_range((unsigned long)kbuf,
> > + (unsigned long)kbuf + dma_size);
>
> Since kbuf is in dma coherent memory, I dont understand why do you flush
> cache.
[kalyani] Agree, not required will fix in next version.
>
> > + ret = eemi_ops->sha_hash(dma_addr, req->nbytes,
> ZYNQMP_SHA3_UPDATE);
> > + dma_free_coherent(dd->dev, dma_size, kbuf, dma_addr);
>
> Since your update function does not return/write any result, I suppose that
> the resulat is kept in hardware, so what happen if two hash process happen
> in parallel ?
[kalyani] yes, the result will be stored in SHA3 engine.
Firmware don't have the support to process 2 hash requests in parallel using IPI
> Furthermore, how do you have tested import/export function ?
> Anyway, I am sure they are totally buggy.
>
[kalyani] I will verify and fix in the next version
> > +
> > + return ret;
> > +}
> > +
> > +static int zynqmp_sha_final(struct ahash_request *req) {
> > + const struct zynqmp_eemi_ops *eemi_ops =
> zynqmp_pm_get_eemi_ops();
> > + struct zynqmp_sha_ctx *tctx = crypto_tfm_ctx(req->base.tfm);
> > + struct zynqmp_sha_dev *dd = tctx->dd;
> > + size_t dma_size = SHA384_DIGEST_SIZE;
> > + dma_addr_t dma_addr;
> > + char *kbuf;
> > + int ret;
> > +
> > + if (!eemi_ops || !eemi_ops->sha_hash)
> > + return -ENOTSUPP;
>
> You can do this check at probe time.
[kalyani] Yes, will fix in next version
>
> > +static int zynqmp_sha_finup(struct ahash_request *req) {
> > + zynqmp_sha_update(req);
> > + zynqmp_sha_final(req);
> > +
> > + return 0;
> > +}
> > +
> > +static int zynqmp_sha_digest(struct ahash_request *req) {
> > + zynqmp_sha_init(req);
> > + zynqmp_sha_update(req);
> > + zynqmp_sha_final(req);
> > +
> > + return 0;
> > +}
>
> So you ignore the return value of
> zynqmp_sha_init/zynqmp_sha_update/zynqmp_sha_final().
>
> > +static int zynqmp_sha_probe(struct platform_device *pdev) {
> > + struct zynqmp_sha_dev *sha_dd;
> > + struct device *dev = &pdev->dev;
> > + int err;
> > +
> > + sha_dd = devm_kzalloc(&pdev->dev, sizeof(*sha_dd),
> GFP_KERNEL);
> > + if (!sha_dd)
> > + return -ENOMEM;
> > +
> > + sha_dd->dev = dev;
> > + platform_set_drvdata(pdev, sha_dd);
> > + INIT_LIST_HEAD(&sha_dd->list);
> > + spin_lock_init(&sha_dd->lock);
> > + crypto_init_queue(&sha_dd->queue,
> ZYNQMP_SHA_QUEUE_LENGTH);
>
> As already said in my last review, why init the queue if you do not use it ?
>
>
> > + spin_lock(&zynqmp_sha.lock);
> > + list_add_tail(&sha_dd->list, &zynqmp_sha.dev_list);
> > + spin_unlock(&zynqmp_sha.lock);
>
> Why do you maintain a device list ?
> Clearly your current driver support only one hardware instance.
[kalyani] True, driver support only one HW instance , will fix in the next version

Regards,
kalyani
>
> Regards

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